Orbital space tourism is a niche industry at the moment, but business could really boom if costs come down by a couple of orders of magnitude, a new study asserts.

To date, only seven people -- beginning with multimillionaire businessman Dennis Tito in April 2001-- have paid to launch into Earth orbit, and they've reportedly plunked down between $20 million and $35 million for the experience.

Those are not the numbers of a thriving industry. But things could change dramatically if prices drop significantly -- down to about $500,000 per seat or so. That reduced rate could lure in hundreds of thousands of customers for orbital tourist trips, potentially generating revenues in excess of $100 billion per year, according to the study.